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Abstract:

A system for generating a digital representation of a video signal
comprised of a sequence of video frames which each include two video
fields of a duration such that the video plays at a first prespecified
rate of frames per second. The sequence of video frames includes a
prespecified number of redundant video fields. Redundant video fields in
the video frame sequence are identified by a video processor, and the
video frame sequence is digitized by an analog to digital converter,
excluding the identified redundant video fields. The digitized video
frames are then compressed by a video compressor to generate a digital
representation of the video signal which plays at a second prespecified
rate of frames per second.

Claims:

1. An apparatus comprising:a random access computer readable medium for
storing a plurality of sequences of digital images from one or more
sources of frames captured for playback at a rate of 24 frames per
second, wherein each of the sequences of digital images is stored as a
data file of a file system of a computer and has images having a
one-to-one correspondence with the rate of 24 frames per second;a
nonlinear editing system, including:means for permitting a user to
specify scenes from the sequences of digital images stored in the data
files on the random access computer readable medium, wherein a scene is
defined by a reference to a data file storing a selected one of the
sequences of digital images and by frame points designated in the
selected sequence of digital images, wherein the frame points may be
designated at any frame boundary using a metric based on the playback
rate of 24 frames per second;means for permitting a user to specify a
sequence of one or more specified scenes;selection means for enabling a
user to select one of a plurality of output frame rates; andmeans for
producing a representation of an audiovisual work from the specified
sequence of scenes in accordance with the selected one of the plurality
of output frame rates.

2. The apparatus of claim 1, wherein one of the plurality of output
formats includes video played back at a rate of 29.97 frames per second.

3. The apparatus of claim 1, wherein one of the plurality of output
formats includes video played back at a rate of 24 frames per second.

4. The apparatus of claim 1, wherein one of the plurality of output
formats includes film.

5. The apparatus of claim 1, wherein one of the plurality of output
formats includes video played back at a rate of 25 frames per second.

6. The apparatus of claim 1, further including:means for storing
information about the designated frame points of each specified scene
from the specified sequence of scenes from the sequences of digital
images using a metric based on the rate of 24 frames per second; andmeans
for updating the stored information with the designated frame points of
each specified scene in response to specification of the scenes from the
sequence of digital images.

7. The apparatus of claim 6, wherein the stored information further
comprises information about the designated frame points of each of the
specified scenes from the specified sequence of scenes from the sequences
of digital images using a metric based on the rate of 29.97 frames per
second.

8. The apparatus of claim 1, wherein the representation of the audiovisual
work is an edit decision list.

9. An apparatus comprising:a random access computer readable medium for
storing a plurality of sequences of digital images from one or more
sources of frames captured for playback at a rate of 24 frames per
second, wherein each of the sequences of digital images is stored as a
data file of a file system of a computer and has images having a
one-to-one correspondence with the rate of 24 frames per second;a
nonlinear editing system, including:means for permitting a user to
specify scenes from the sequences of digital images stored in the data
files on the random access computer readable medium, wherein a scene is
defined by a reference to a data file storing a selected one of the
sequences of digital images and by frame points designated in the
selected sequence of digital images,wherein the frame points may be
designated at any frame boundary using a metric based on the playback
rate of 24 frames per second;means for permitting a user to specify a
sequence of one or more specified scenes;means for storing information
about the designated frame points of each specified scene from the
specified sequence of scenes from the sequences of digital images using a
metric based on the rate of 24 frames per second and a second frame rate
different from the rate of 24 frames per second;means for updating the
stored information with the designated frame points of each specified
scene in response to specification of the scenes from the sequence of
digital images; andmeans for producing an audiovisual work using the
specified sequence of scenes in accordance with a selected one of a
plurality of output frame rates.

10. The apparatus of claim 9, further comprising selection means for
enabling a user to select the selected one of the plurality of output
frame rates.

11. The apparatus of claim 9, wherein one of the plurality of output
formats includes video played back at a rate of 29.97 frames per second.

12. The apparatus of claim 9, wherein one of the plurality of output
formats includes video played back at a rate of 24 frames per second.

13. The apparatus of claim 9, wherein one of the plurality of output
formats includes film.

14. The apparatus of claim 9, wherein one of the plurality of output
formats includes video played back at a rate of 25 frames per second.

15. The apparatus of claim 9, wherein the stored information further
comprises information about the designated frame points of each of the
specified scenes from the specified sequence of scenes from the sequences
of digital images using a metric based on the rate of 29.97 frames per
second.

Description:

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001]This application is a CONTINUATION application of and claims the
benefit under 35 U.S.C §120 of the filing date of: [0002]U.S.
patent application Ser. No. 10/657,800, filed Sep. 8, 2003, entitled
ELECTRONIC FILM EDITING SYSTEM USING BOTH FILM AND VIDEOTAPE FORMAT,
pending, which is a continuation of U.S. patent application Ser. No.
09/304,932, filed May 4, 1999, entitled ELECTRONIC FILM EDITING SYSTEM
USING BOTH FILM AND VIDEOTAPE FORMAT, issued as U.S. Pat. No. 6,618,547
on Sep. 9, 2003, which is a continuation of both U.S. patent application
Ser. No. 08/393,877, filed Feb. 24, 1995, entitled ELECTRONIC FILM
EDITING SYSTEM USING BOTH FILM AND VIDEOTAPE FORMAT, and now U.S. Pat.
No. 5,930,445, issued Jul. 27, 1999, and U.S. patent application Ser. No.
08/393,886, filed Feb. 24, 1995, entitled ELECTRONIC FILM EDITING SYSTEM
USING BOTH FILM AND VIDEOTAPE FORMAT, and now U.S. Pat. No. 5,905,841,
issued May 18, 1999, which are a divisional application, and continuation
application, respectively, of application Ser. No. 07/908,192, filed Jul.
1, 1992, now abandoned; and [0003]U.S. patent application Ser. No.
09/304,932, filed May 4, 1999, entitled ELECTRONIC FILM EDITING SYSTEM
USING BOTH FILM AND VIDEOTAPE FORMAT, issued as U.S. Pat. No. 6,618,547
on Sep. 9, 2003, which is a continuation of both U.S. patent application
Ser. No. 08/393,877, filed Feb. 24, 1995, entitled ELECTRONIC FILM
EDITING SYSTEM USING BOTH FILM AND VIDEOTAPE FORMAT, and now U.S. Pat.
No. 5,930,445, issued Jul. 27, 1999, and U.S. patent application Ser. No.
08/393,886, filed Feb. 24, 1995, entitled ELECTRONIC FILM EDITING SYSTEM
USING BOTH FILM AND VIDEOTAPE FORMAT, and now U.S. Pat. No. 5,905,841,
issued May 18, 1999, which are a divisional application, and continuation
application, respectively, of application Ser. No. 07/908,192, filed Jul.
1, 1992, now abandoned; and [0004]U.S. patent application Ser. No.
08/393,877, filed Feb. 24, 1995, entitled ELECTRONIC FILM EDITING SYSTEM
USING BOTH FILM AND VIDEOTAPE FORMAT, and now U.S. Pat. No. 5,930,445,
issued Jul. 27, 1999, which is a divisional application of application
Ser. No. 07/908,192, filed Jul. 1, 1992, now abandoned; and [0005]U.S.
patent application Ser. No. 08/393,886, filed Feb. 24, 1995, entitled
ELECTRONIC FILM EDITING SYSTEM USING BOTH FILM AND VIDEOTAPE FORMAT, and
now U.S. Pat. No. 5,905,841, issued May 18, 1999, which is a continuation
of application Ser. No. 07/908,192, filed Jul. 1, 1992, now abandoned;
and [0006]U.S. patent application Ser. No. 07/908,192, filed Jul. 1,
1992, now abandoned.

[0008]Film video and audio source material is frequently edited digitally
using a computer system, such as the Avid/1 Media Composer from Avid
Technology, Inc., of Tewksbury, Mass., which generates a digital
representation of a source film, allowing a film editor to edit the
digital version, rather than the film source itself. This editing
technique provides great precision and flexibility in the editing
process, and is thus gaining popularity over the old style of film
editing using a flatbed editor.

[0009]The Avid/1 Media Composer accepts a videotape version of a source
film, created by transferring the film to videotape using the so-called
telecine process, and digitizes the videotape version for editing via
manipulation by computer. The operation of the Media Composer is
described more fully in copending application U.S. Ser. No. 07/866,829,
filed Apr. 10, 1992, and entitled Improved Media Composer. The teachings
of that application are incorporated herein by reference. Editing of the
digitized film version is performed on the Media Composer computer using
CRT monitors for displaying the digitized videotape, with the edit
details being based on videotape timecode specifications. Once editing is
complete, the Media Composer creates an edited videotape and a
corresponding edit decision list (EDL) which documents the videotape
timecode specification details of the edited videotape. The film editor
uses this EDL to specify a cut and assemble list for editing the source
film. While providing many advantages over the old style flatbed film
editing technique, this electronic editing technique is found to be
cumbersome for some film editors who are unaccustomed to videotape
timecode specifications.

SUMMARY OF THE INVENTION

[0010]In general, in one aspect, the invention provides a system for
generating a digital representation of a video signal comprised of a
sequence of video frames which each include two video fields of a
duration such that the video plays at a first prespecified rate of frames
per second. The sequence of video frames includes a prespecified number
of redundant video fields. In the invention, redundant video fields in
the video frame sequence are identified by a video processor, and the
video frame sequence is digitized by an analog to digital converter,
excluding the identified redundant video fields. The digitized video
frames axe then compressed by a video compressor to generate a digital
representation of the video signal which plays at a second prespecified
rate of frames per second.

[0011]In preferred embodiments, the invention further provides for storing
the digitized representation of the video signal on a digital storage
apparatus. The redundant video fields are identified by assigning a
capture mask value to each video field in the video frame sequence, the
capture mask value of a field being a "0" if the field is redundant, and
the capture mask value of a field being a "1" for all other video fields.
A video frame grabber processes the video frame sequence based on the
capture mask values to exclude the identified redundant video frames from
being digitized. The video compressor compresses the video frames based
on JPEG video compression.

[0012]In other preferred embodiments, the first prespecified video play
rate is 29.97 frames per second and the second prespecified digital video
play rate is 24 frames per second. The rate of the analog video signal is
increased from 29.97 frames per second to 30 frames per second before the
step of digitizing the video frame sequence. In further preferred
embodiments, the analog video signal is a video representation of film
shot at 24 frames per second, and the digital video play rate of 24
frames per second corresponds to the 24 frames per second film shooting
rate. The analog video signal is a representation of film that is
transferred to the video representation using a telecine apparatus.

[0013]In general, in another aspect, the invention provides an electronic
editing system for digitally editing film shot at a first prespecified
rate and converted to an analog video representation at a second
prespecified rate. The editing system includes analog to digital
converting circuitry for accepting the analog video representation of the
film, adjusting the rate of the analog video such that the rate
corresponds to the first prespecified rate at which the film was shot,
and digitizing the adjusted analog video to generate a corresponding
digital representation of the film. Further included is a digital storage
apparatus for storing the digital representation of the film, and
computing apparatus for processing the stored digital representation of
the film to electronically edit the film and correspondingly edit the
stored digital representation of the film.

[0014]In preferred embodiments, the system further includes digital to
analog converting circuitry for converting the edited digital
representation of the film to an analog video representation of the film,
adjusting the rate of the analog video from the first prespecified rate
to the second prespecified video rate, and outputting the adjusted analog
video. Preferably, the analog video representation of the film accepted
by the analog to digital converting circuitry is an NTSC videotape. The
apparatus for storing the digital representation of the film also stores
a digitized version of a film transfer log corresponding to the digital
representation of the film. The system includes display apparatus for
displaying the digitized version of the film as the film is
electronically edited and displaying a metric for tracking the location
of a segment of the film as the segment is displayed, the metric being
based on either film footage code or video time code, as specified by the
system user.

[0015]The electronic editing system of the invention allows users to
provide the system with film formatted on standard videotapes, NTSC
tapes, for example, and yet allows the video to be digitally edited as if
it were film, i.e., running at film speed, as is preferred by most film
editors. By reformatting the analog video as it is digitized, the system
provides the ability to electronically edit film based on the same metric
used in conventional film editing.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016]FIG. 1 is a schematic diagram of the electronic editing system of
the invention.

[0017]FIG. 2 is a diagram of the telecine film-tape transfer pulldown
scheme.

[0018]FIG. 3 is a schematic diagram of the telecine film-tape transfer
system.

[0019]FIG. 4 is an Evertz Film Transfer Log produced by the telecine
transfer system and processed by the editing system of the invention.

[0020]FIG. 5 is an illustration of a video screen showing the electronic
bin generated by the editing system of the invention.

[0021]FIG. 6 is a diagram of the scheme employed by the editing system in
digitizing a video input to the system.

[0022]FIG. 7 is an illustration of a video screen showing the digitized
video to be edited on the electronic editing system of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0023]Referring to FIG. 1, there is shown the electronic editing system of
the invention 10, including two CRT displays 12, 14 for displaying
digitized film during an editing session, and an audio output device 16,
for example, a pair of speakers, for playing digitized audio during an
editing session. The displays 12, 14 and audio output 16 are all
controlled by a computer 18. Preferably, the computer is a Macintosh®
IIci, IIfx, Quadra 900, or Quadra 950 all of which are
available from Apple Computer, Inc., of Cupertino, Calif. The system
includes a video tape recorder (VTR) 20 for accepting an electronic
version of film footage, which is preprocessed and digitized by a video
analog to digital converter (A/D) 26. A timing circuit 28 controls the
speed of the video being digitized, as described below. A video
compressor 30 is connected to the video A/D for compressing the
electronic image data to be manipulated by the computer 18. An audio A/D
22 and audio processor 24 process audio information from the electronic
version of film footage in parallel with the video processing. Disc
storage 32 communicates with the computer to provide memory storage for
digitized electronic image data. This disc storage may be optical,
magnetic, or some other suitable media. The editing system is
user-interfaced via a keyboard 34, or some other suitable user control
interface.

[0024]In operation, video and audio source material from a film which has
been transferred to a videotape is received by the system via the video
tape recorder 20, and is preprocessed and digitized by the audio A/D 22,
audio processor 24, video A/D 26, and video compressor 30, before being
stored in the disc storage 32. The computer is programmed to display the
digitized source video on a first of the CRTs 12 and play the
accompanying digitized source audio on the audio output 16. Typically
source material is displayed in one window 36 of the first CRT 12 and
edited material is displayed in a second window 38 of that CRT. Control
functions, edit update information, and commands input from the keyboard
32 are typically displayed on the second system CRT 14.

[0025]Once a film is input to the system, a film editor may electronically
edit the film using the keyboard to make edit decision commands. As will
be explained in detail below, the electronic editing system provides the
film editor with great flexibility, in that the video displayed, on the
system CRT 12 may be measured and controlled in either the domain of film
footage or the domain of videotape time code. This flexibility provides
many advantages over prior electronic editing systems. At the end of an
editing session, the electronic editing system provides the film editor
with an edited videotape and both tape and film edit command lists for
effecting the edits from the session on film or videotape.

[0026]As explained above, the electronic editing system 10 requires a
videotape version of a film for electronic manipulation of that film.
Such a tape is preferably generated by a standard film-tape transfer
process, the telecine process, which preferably uses the Time Logic
Controller® telecine (TLC), a device that converts film into a video
signal, then records the signal on videotape. A TLC controls the
film-tape transfer more precisely than non-TLC systems. In addition, it
outputs a report, described below, that includes video format
specifications, i.e., timecode, edge number, audio timecode, scene, and
take for each reference frame in each tape, thereby eliminating the need
to search through the video or film footage manually to find the data
required for creating a log of video playing particulars. Other telecine
systems may be used, however, depending on particular applications.

[0027]Transfer from film to tape is complicated by the fact that film and
video play at different rates-film plays at 24 frames per second (fps),
whereas PAL video plays at 25 fps and NTSC (National Television Standards
Committee) video plays at 29.97 fps. If the film is shot at the standard
rate of 24 fps and then transferred to 29.97 fps NTSC video, the
difference between the film and video play rates is large (and typically
unacceptable). As a result, the film speed, must be adjusted to
accommodate the fractional tape speed, and some film frames must be
duplicated during the transfer so that both versions have the same
duration. However, if the film is shot at 29.97 fps, then transferring
the footage to NTSC video is simple. Each film frame is then transferred
directly to a video frame, as there are the same number of film and video
frames per second.

[0028]Considering the most common case, in which 24 fps film is to be
transferred to 29.97 fps NTSC videotape, the telecine process must
provide both a scheme for slowing the film and a frame duplication
scheme. The film is slowed down by the telecine apparatus by 0.1% of the
normal film speed, to 23.976 fps, so that when the transfer is made, the
tape runs at 29.97 fps, rather than 30 fps. To illustrate the frame
duplication scheme, in the simplest case, and disregarding the film
slow-down requirement, one second of film would be transferred to one
second of video. The one second of film would include 24 frames of film
footage, but the corresponding one second of video would require 30
frames of footage. To accommodate this discrepancy, the telecine process
duplicates one film frame out of every four as the film is transferred to
tape, so that for each second of film footage, the corresponding second
of tape includes six extra frames.

[0029]Each video frame generated by the telecine process is actually a
composite of two video fields: an odd field, which is a scan of the odd
lines on a video screen, and an even field, which is a scan of the even
lines. A video field consists of 2621/2 scan lines, or passes of an
electron beam across a video screen. To create a full video frame
comprised of 525 scan lines, an odd field, or scan of the odd lines, is
followed by an even field, or scan of the even lines. Thus, when a
duplicate video frame is generated and added in the telecine process,
duplicate video fields are actually created. During play of the resulting
tape, each two video fields are interlaced to make a single frame by
scanning of the odd lines (field one) followed by scanning of the even
lines (field two) to create a complete frame of NTSC video.

[0030]There are two possible systems for creating duplicate video fields
in the telecine process, those systems being known as 2-3 pulldown and
3-2 pulldown. The result of the 2-3 pulldown process is schematically
illustrated in FIG. 2. In a film-tape transfer using 2-3 pulldown, the
first film frame (A in FIG. 2) is transferred to 2 video fields AA of the
first video frame; the nest film frame B is transferred to 3 video fields
BBB, or one and one half video frames, film frame C is transferred to two
video fields CC, and so on. This 2-3 pulldown sequence is also referred
to as a SMPTE-A transfer. In a 3-2 pulldown transfer process, this
sequence of duplication is reversed; the first film frame A would be
mapped to 3 video fields, the nest film frame B would be mapped to 2
video fields, and so on. This 3-2 pulldown sequence is also referred to
as a SMPTE-B transfer. In either case, 4 frames of film are converted
into 10 video fields, or 5 frames of video footage. When a 2-3 pulldown
sequence is used, an A, B, C, D sequence in the original film footage
creates an AA, BB, BC, CD, DD sequence of fields in the video footage, as
shown in FIG. 2. The telecine process slows down the film before the
frame transfer and duplication process, so that the generated video
frames run at 29.97 fps.

[0031]Referring to FIG. 3, as discussed above, the telecine 36 produces a
video signal from the film; the video is generated to run at 29.97 fps
and includes redundant film frames from the pulldown scheme. NAGRA®
audio timecode is the typical and preferable system used with films for
tracking the film to its corresponding audiotape, rehiring the telecine
process, a corresponding audio track 38 is generated based on the
NAGRA® and is slowed down by 0.1% so that it is synchronized to the
slowed film speed. The sound from the film audiotrack is provided at 60
Hz; a timing reference 40 at 59.94 Hz slows the audio down as required.
Thus, the telecine process provides, for recordation on a videotape 48
via a videotape recorder 20, a video signal (V in the figure),
corresponding audio tracks, A1-An, and the audio timecode
(audio TC).

[0032]A further film-tape correspondence is generated by the telecine
process. This is required because, in addition to the difference between
film and video play rates, the two media employ different systems for
measuring and locating footage. Film is measured in feet and frames.
Specific footage is located using edge numbers, also called edge code or
latent edge numbers, which are burned into the film. For example, Kodak
film provides Keykode® on the film to track footage. The numbers
appear once every 16 frames, or once every foot, on 35 mm film. The
numbers appear once every 20 frames, or every half foot, on 16 mm film.
Note that 35 mm film has 16 frames per foot, while 16 mm film has 40
frames per foot. Each edge number includes a code for the film
manufacturer and the film type, the reel, and a footage counter. Frames
between marked edge numbers are identified using edge code numbers and
frame offsets. The frame offset represents the frame's distance from the
preceding edge number.

[0033]Videotape footage is tracked and measured using a time-base system.
Time code is applied to the videotape and is read by a time code reader.
The time code itself is represented using an 8-digit format:
XX-XX-XX-XX--hours:minutes:seconds:frames. For example, a frame occurring
at 11 minutes, 27 seconds, and 19 frames into the tape would be
represented as 00:11:27:19.

[0034]It is preferable that during the telecine conversion, a log, called
a Film Transfer Log (FTL), is created that makes a correspondence between
the film, length-base and the video time-base. The FTL documents the
relationship between one videotape and the raw film footage used to
create that tape, using so-called sync points. A sync point is a
distinctive frame located at the beginning of a section of film, say, a
clip, or scene, which has been transferred to a tape. The following
information documents a sync point: edge number of the sync point in the
film footage, time code of the same frame in the video footage, the type
of pulldown sequence used in the transfer, i.e., 2-3 pulldown or 3-2
pulldown, and the pulldown mode of the video frame, i.e., which of the A,
B, C, and D frames in each film five-frame series corresponds to the sync
point frame.

[0035]As shown in FIG. 3, an Evertz 4015 processor accepts the video
signal from the telecine and the audio TC corresponding to the audiotrack
and produces a timecode based on a synchronization of the audio and
video. Then an Evertz PC 44 produces an Evertz FTL 46 which includes the
sync point information defined above.

[0036]FIG. 4 illustrates a typical Evertz FTL 46. Each column of the log,
specified with a unique Record #, corresponds to one clip, or scene on
the video. Of particular importance in this log is the VideoTape Time
Code In (VTTC IN) column 50 and VideoTape Time Code Out (VTTC OUT) column
52. For each scene, these columns note the video time code of the scene
start and finish. In a corresponding manner, the Keyin column 54 and
Keyout column 56 note the same points in film footage and frames. The
Pullin column 58 and Pullout column 60 specify which of the A, B, C, or D
frames in the pulldown sequence correspond to the frame at the start of
the scene and the close of the scene. Thus, the FTL gives scene sync
information that corresponds to both the video domain and the film
domain.

[0037]The electronic editing system of the invention accepts a videotape
produced by the telecine process and an Evertz FTL, stored on, for
example, a floppy disk. When the FTL data on the disk is entered into the
system, the system creates a corresponding bin in memory, stored on the
system disc, in analogy to a film bin, in which film clips are stored for
editing. The electronic bin contains all fields necessary for film
editing, all comments, and all descriptions. The particulars of the bin
are displayed for the user on one of the system's CRTs. FIG. 5
illustrates the display of the bin. It corresponds directly to the Evertz
FTL. The "Start" and "End" columns of the bin correspond to the VideoTape
Time Code In and VideoTape Time Code Out columns of the FTL: The "KN
Start" and "KN End" columns of the bin correspond to the Keyin and Keyout
columns of the FTL. During an editing session, the bin keeps track of the
editing changes in both the video time-base and the film footage-base, as
described below. Thus, the bin provides the film editor with the
flexibility of keeping track of edits in either of the metrics.

[0038]Referring again to FIG. 1, when the electronic editing system 10 is
provided with a videotape at the start of a film editing session, the
videotape recorder 20 provides to the computer 18 the video and audio
signals corresponding to the bin. The video signal is first processed by
a video A/D coprocessor 26, such as the NuVista board made by TrueVision
of Indianapolis, Ind. A suitable video coprocessor includes a video frame
grabber which converts analog video information into digital information.
The video coprocessor has a memory which is configured using a
coprocessor such as the TI34010 made by Texas Instruments, to provide an
output data path to feed to the video compression circuitry, such as JPEG
circuitry, available as chip CL550B from C-Cube of Milpitas, Calif. Such
a configuration can be performed using techniques known in the art. A
timing circuit 28 controls the speed of the video signal as it is
processed.

[0039]In operation, the video A/D 26 processes the video signal to
reformat the signal so that the video represented by the signal
corresponds to film speed, rather than videotape speed. The reformatted
signal is then digitized, compressed, and stored in the computer for
electronic film editing. This reformatting process allows users to
provide the editing system with standard videotapes, in NTSC format, yet
allows the video to be edited as if it were film, i.e., running at film
speed, as is preferred by most film editors.

[0040]Referring also to FIG. 6, in this reformatting process, the speed of
the video from the videotape is increased from 29.97 fps to 30 fps, as
commanded by the timing circuitry 28 (FIG. 1). Then the fields of the
video are scanned by the system, and based on the pulldown sequence and
pulldown mode specified for each scene by the bin, the redundant video
fields added by the telecine process are noted, and then ignored, while
the other, nonredundant, fields are digitized and compressed into digital
frames. More specifically, a so-called "capture mask" is created for the
sequence of video fields; those fields which are redundant are assigned a
capture value of "0" while all other fields are assigned a capture value
of "1". The system coprocessor reads the entire capture mask and only
captures those analog video fields corresponding to a "1" capture value,
ignoring all other fields. In this way, the original film frame sequence
is reconstructed from the video frame sequence. Once all the nonredundant
fields are captured, the fields are batch digitized and compressed to
produce digitized frames.

[0041]Assuming the use of the 2-3 pulldown scheme, as discussed above, in
the capture process, the first two analog video fields (AA in FIG. 6)
would each be assigned a capture value of "1", and thus would be
designated as the first digital frame; the next two analog video fields
BB would also each be assigned a capture value of "1", and be designated
as the second digital frame; but the fifth analog video field B, which is
redundant, would be assigned a capture value of "0", and would be
ignored, and so on. Thus, this process removes the redundant 6 frames
added by the telecine process for each film second from the video,
thereby producing a digitized representation which corresponds directly
to the 24 fps film from which the video was made. This process is
possible for either the 2-3 or 3-2 pulldown scheme because the bin
specifies the information necessary to distinguish between the two
schemes, and the starting frame (i.e., A, B, C, or D) of either sequence
is given for each scene.

[0042]Appendix A of this application consists of an example of assembly
language code for the Macintosh® computer and the TI 34010 coprocessor
for performing the reformatting process. This code is copyrighted, and
all copyrights are reserved.

[0043]Referring again to FIG. 1, an audio A/D 22 accepts audio from a
videotape input to the editing system, and like the video AD 26,
increases the audio speed back to 100%, based on the command of the
timing circuitry 28. The audio is digitized and then processed by the
audio processor 24, to provide digitized audio corresponding to the
reformatted and digitized video. At the completion of this digitization
process, the editing system has a complete digital representation of the
source film in film format, i.e., 24 fps, and has created a bin with both
film footage and video timecode information corresponding to the digital
representation, so that electronic editing in either time-base or
footage-base may begin.

[0044]There are traditionally three different types of film productions
that shoot on film, each type having different requirements of the
electronic editing system. The first film production type, commercials,
typically involves shooting on 35 mm film, transferring the film to a
videotape version using the telecine process, editing the video based on
the NTSC standard, and never editing the actual film footage, which is
not again needed after the film is transferred to video. Thus, the
electronic editing is here preferably based on video timecode
specifications, not film footage specifications, and an NTSC video is
preferably produced at the end of the edit process. The electronic
commercial edit should also preferably provide an edit decision list
(EDL) that refers back to the video; the edited version of this video is
typically what is actually played as the final commercial.

[0045]The second production type, episodic film, involves shooting on
either 35 or 16 mm film, and producing an NTSC videotape version and
additionally, an (optional) edited film version for distribution in
markets such as HDTV (High Definition Television) or foreign countries.
To produce the edited film footage for the film version, the film is
transferred to videotape using the telecine process, and electronic
editing of the film is here preferably accomplished based on film
footage, and should produce a cutlist, based on film footage
specifications, from which the original film is cut and transferred to
the NTSC format. To produce a video version, the videotape is then
preferably edited based on video timecode specifications to produce an
EDL for creating an edited video version.

[0046]The third film production type, feature film, typically involves
shooting on 35 mm film, and produces a final film product; thus
electronic editing is here preferably based on film footage
specifications to produce a cutlist for creating a final film version.

[0047]The user interface of the electronic editing system is designed to
accommodate film editors concerned with any of the three film production
types given above. As shown in FIG. 7, the video display CRT 12 of the
system, which includes the source video window 36 and edited video window
38, displays metrics 37, 39 for tracking the position of digital frames
in a scene sequence currently being played in the source window or the
edit window. These metrics may be in either film footage format or video
time code format, whichever is preferred by the user. Thus, those film
editors who prefer film footage notation may edit in that domain, while
those film editors who prefer video timecode notation may edit in that
domain. In either case, the digitized frames correspond exactly with the
24 fps speed of the original source film, rather than the 29.97 fps speed
of videotape, so that the electronic edits produced by the electronic
editing correspond exactly with the film edits, as if the film were being
edited on an old-style flat bed editor.

[0048]As an example of an editing session, one scene could be selected
from the bin and played on the source window 36 of the system CRT display
12. A film editor could designate frame points to be moved or cut in
either timecode or film footage format. Correspondingly, audio points
could be designated to be moved or the audio level increased (or
decreased). When it is desired to preview a video version of such edits,
an NTSC video is created by the system based on the sync information in
the electronic bin, from the system disc storage, to produce either a
so-called rough cut video, or a final video version. In this process, the
system generates an analog version of the digital video signal and
restores the redundant video frames necessary for producing the NTSC
video rate. The system also produces a corresponding analog audio track
and decreases the audio speed so that the audio is synchronized with the
video. In this way, the system essentially mimics the telecine process by
slowing down the video and audio and producing a 29.97 fps videotape
based on a 24 fps source.

[0049]Referring again to FIG. 1, in creating an NTSC video from a
digitized film version, the video compressor 30 retrieves the digitized
video frames from the computer 18 and based on the electronic bin
information, designates video fields. The video A/D 26 then creates an
analog version of the video frames and processes the frames using a
pulldown scheme like that illustrated in FIG. 2 to introduce redundant
video frames. The video speed is then controlled by the timing circuit 28
to produce 29.97 fps video as required for an NTSC videotape.
Correspondingly, the system audio process 24 and audio A/D 22 processes
the digital audio signal based on the electronic bin to generate an
analog version of the signal, and then slows the signal by 0.1% to
synchronize the audio with the NTSC video. The final video and audio
signals are sent to the videotape recorder 20, which records the signals
on a videotape.

[0050]The electronic editing system may be programmed to produce an edit
listing appropriate to the particular media on which the finalized
version of the film source material is to appear. If the source film
material is to be finalized as film, the system may be specified to
produce a cut list. The cut list is a guide for conforming the film
negative to the edited video copy of the film footage. It includes a pull
list and an assemble list. The assemble List provides a list of cuts in
the order in which they must be spliced together on the film. The pull
list provides a reel-by-reel listing of each film cut. Each of these
lists specifies the sync points for the cuts based on film footage and
frame keycode, as if the film had been edited on a flatbed editor. If the
source film material is to be finalized as video, the system may be
specified to produce an edit decision list (EDL). The EDL specifies sync
points in video time code, as opposed to film footage. The editing system
generates the requested edit fists based on the electronic bin; as the
film is electronically edited, the bin reflects those edits and thus is a
revised listing of sync points corresponding to the edited film version.
Because the bin is programmed to specify sync points in both film,
footage and video timecode, the editing system has direct access to
either format, and can thereby generate the requested EDL or assemble and
pull lists. Appendix B consists of examples of an EDL, assemble lists,
and pull lists, all produced by the electronic editing system. Thus, at
the end of an electronic film edit, the editing system provides a film
editor with an NTSC videotape of the film edits and a edit list for
either film or videotape.

[0051]Other embodiments of the invention are within the scope of the
claims.